Erratic AFR's, running rich

[Tommy]

Ok, so after I had the CPE downpipe taken off and had the stock cats put back on, I started to notice the car jerking, It was subtle at first but has progressively gotten worse. Another member did some logs and fuel pressure was fine, stock BPV was holding above 14psi but AFR's were all over the place and it was running rich. We also swapped MAF's and it was not the MAF. All I have right now is Torque Pro for monitoring. What should I be looking for? My suspicion has been the o2 sensors, thinking maybe they screwed them up during the swap. Driving home tonight at 65 on flat road, AFR's all over, second o2 was around .7v, up and down around there anyways.

[fivefingerdeathpunch]

leak of some sort or messed up o2 like you said. no cels i presume?

[Tommy]

The only code I have thst comes back is p0126, which is related to the thermostat.

[Tommy]

Going to do a log tonight so people can see what I am getting. I was told to disconnect SWAS to make sure that was not causing the issue. Makes a little sense and it's worth a shot at this point.

[MattJackson86]

Have you tried resetting the ECU? Just unplug battery for 30 seconds and then have the car re-learn the fuel trims.

[Tommy]

Originally Posted by MattJackson86 Have you tried resetting the ECU? Just unplug battery for 30 seconds and then have the car re-learn the fuel trims.

I've been down that road a few times.

[Tommy]

Finally getting logs posted. Hope they are helpful but if not, tell me what PID's to add. going for another long run today so logs won't be an issue. @trf5000, , can you take a look too?

[Tommy]

bump

[trf5000]

@Tommy, can you get a wot log? Its tough to tell when your not in the throttle for a long period of time. Start at about 2500 RPM and run up to about 6500 rpm in 4th gear.

[Tommy]

Originally Posted by trf5000 @Tommy, can you get a wot log? Its tough to tell when your not in the throttle for a long period of time. Start at about 2500 RPM and run up to about 6500 rpm in 4th gear.

Sure can. How long do you want me to hold at 6500? Any PID's missing you want to see?

[trf5000]

Originally Posted by Tommy Sure can. How long do you want me to hold at 6500? Any PID's missing you want to see?

You don't need to hold, just need to go from 2500 to 6500 WOT, and post that what with you currently have.

[BigRedSpecial]

Watching this closely... I'm having the same issue. In my case AFR is dropping to 8-9 while in closed loop and under light load/throttle, around 2000-2500 rpm. Fuel pressure is high (maybe too high... last night I was hitting 1700psi at VERY low load). Trims are fine, no knock, nothing apparent. I was throwing an oxygen sensor code so I blamed it on that; replaced the sensor and the problem was still there.

I reflashed to a V2.31 map (was running a V2.1 modified for 17.0:1 AFR); it's been fine since but the problem came and went previously so time will tell.

I did read one thread on here where someone had similar troubles; oxygen sensor codes and all... turned out in his case to be an ECU shitting the bed. Hope that isn't the case here, for either of us

[Mistersix]

Originally Posted by BigRedSpecial Watching this closely... I'm having the same issue. In my case AFR is dropping to 8-9 while in closed loop and under light load/throttle, around 2000-2500 rpm. Fuel pressure is high (maybe too high... last night I was hitting 1700psi at VERY low load). Trims are fine, no knock, nothing apparent. I was throwing an oxygen sensor code so I blamed it on that; replaced the sensor and the problem was still there. I reflashed to a V2.31 map (was running a V2.1 modified for 17.0:1 AFR); it's been fine since but the problem came and went previously so time will tell. I did read one thread on here where someone had similar troubles; oxygen sensor codes and all... turned out in his case to be an ECU shitting the bed. Hope that isn't the case here, for either of us

Found this thread threw searching for an answer as i seem to have the same issue going. Noticed it while cruising on the highway at 60 some mph. Afr's dip down low and stay there the whole time. This only seems to happen when there is a good bit of load at low rpm/part throttle. e.g. keeping speed while climbing a long hill such as in the log below. You'll notice as i crest the hill, load goes down, and afr's begin to settle.

Does any one have any insight?

[BigRedSpecial]

Mine was fine during highway cruising... I used to see the problem while leaving from a light or similar, and after it happened it would occur while idling. Not sure what your problem could be... I'm at work so I can't look at the log.

In my case, after I flashed the new map the problem didn't reoccur.

[Mistersix]

Originally Posted by BigRedSpecial Mine was fine during highway cruising... I used to see the problem while leaving from a light or similar, and after it happened it would occur while idling. Not sure what your problem could be... I'm at work so I can't look at the log. In my case, after I flashed the new map the problem didn't reoccur.

It can happen rolling away from a stop for me as well. Driving gingerly, if i hold a gear at part throttle the afr will just work its way down to a rich condition. I'll try to get a log of that.

Its very noticeable. I can feel it in the car when its happening. Its actually what prompted me to look for something. It seems to be a correlation between load and throttle position. There's a strong enrichment taking place and i'm not sure why. If i nudge the throttle it goes away and afr's go back to targeted.

[BigRedSpecial]

Can't say mine ever gave any trouble on the highway. Any CELs?

[Mistersix]

No cel's. I've got another log showing rich conditions. It seems anytime the there's very little to no boost and the boost gauge is around zero i can feel the engine start to bog, then the sound of the turbo changes and afr's slowly work their way down into the 9's and 8's. It gets louder almost as if the BPV is opening slightly, too.

[BigRedSpecial]

Sounds like it could be a boost leak to me... Engine isn't seeing the amount of air the MAF is reading, so AFR goes pig rich

[Mistersix]

could be. I need to get in there and peek around.

[x09MS3GT]

Sorry to bump this old thread. But the past 2 months ive been banging my fucking head off a wall trying every possible idea as to what the hell is going on with my car, and this thread is exactly the problem im seeing as well

2 Months ago, i started my car up as normal in the cold. Was about 28 degrees out. Car started up without hesitation just as it always does. As the coolant warms up the AFR rises up to about 14.5 to 14.7 at idle, when all of a sudden, it starts dropping down, 13's, 12's, 10's , 9 's , 8's. STFT is fucking pegged at -25. Car is struggling to stay running while drowning itself in fuel. I turn it off. Restart the car, problem is gone. On the way home. Crusing in 4th gear, 40 mph, steady pedal input, watching A/F , its sitting at 14.6 , 14.7 . Then all of a sudden, it drops down to 14.0, climbs back to 15.0, then back down, then back up then back down, then back up. Then settles at 14.7.

I get home, furious as all hell. Reflash current map. Problem is now non existant.

100 miles later, fuel trims are pretty tight. All with in +/- 4 across the board.
Driving hte car to work. It starts doing the same fucking shit again. climbing up and down while crusing with steady pedal input, no movement. Sometimes after a shift, the AFR dips down to 13.8, and sits there as i cruise in a gear with steady pedal input, and it SLOWLY rises back up to 14.6 / 14.7.


Yesterday morning, start the car, AFR pegged at 8.0:1 , drowning itself in fuel, struggling to stay running.


Ive pulled the Primary 02 , cleaned it, ive checked at least 3 times now for boost leaks, ive cleaned my MAF twice. I even put a brand fucking new Filter replacement for the COBB SRI on. Im running out of ideas here.

Has anyone got any ideas ? 02 sensor dying out ? MAF Sensor Eff'd ?
And if so, how with so little miles. I dont get it.

[Tommy]

Dude, I tried everything. The fix was new o2. I went with the NTK from rockauto.com and its been fine since.

[x09MS3GT]

Originally Posted by Tommy Dude, I tried everything. The fix was new o2. I went with the NTK from rockauto.com and its been fine since.

109 bucks vs Mazda auto parts 260 ? Yes please .
Thanks a shit ton man. Great find !

[Mistersix]

I hope this works for you man. Fwiw, my issue turned out to be my factory valve was slowly opening without cause and only at part throttle. I replaced it with a gfb respons and the it solved the issue.

02 sensor is cheaper than a new valve so hope it works out for ya.

[torq]

Just to add to the thread, I'm experimenting with going full vta with the Lex's GA and the Cobb XLE bpv. This is exactly the symptoms I am experiencing, seems like the GA stops the vacuum block at around 0 psi, but if you're not actually in boost the small amount of vacuum will pull the valve open enough so you get a large boost leak and can't advance past 0 psi.

This only occurs if you slowly ramp up the throttle, like you're doing a maf cal. If I just giv'er everything is fine as it transitions from vacuum to boost quickly and the bpv doesn't have a change to leak.

I've gone back and forth with lex a few times but the Cobb XLE won't behave no matter how tight I turn it, always seems to crack open around the 0psi mark. I've ordered a GFB bov, as some people seem to have good luck with that.

[pzr2874]

@Tommy; did you replace the front o2?

[Mistersix]

Originally Posted by torq Just to add to the thread, I'm experimenting with going full vta with the Lex's GA and the Cobb XLE bpv. This is exactly the symptoms I am experiencing, seems like the GA stops the vacuum block at around 0 psi, but if you're not actually in boost the small amount of vacuum will pull the valve open enough so you get a large boost leak and can't advance past 0 psi. This only occurs if you slowly ramp up the throttle, like you're doing a maf cal. If I just giv'er everything is fine as it transitions from vacuum to boost quickly and the bpv doesn't have a change to leak. I've gone back and forth with lex a few times but the Cobb XLE won't behave no matter how tight I turn it, always seems to crack open around the 0psi mark. I've ordered a GFB bov, as some people seem to have good luck with that.

I've not noticed my GFB opening while holding part throttle. My stock one did which is why i got the GFB in the first place.

Honestly the GFB is a great valve. Its compact, adjustable and can be run in several configurations. It could work many different ways. Its really loud. I didn't realize how loud till now that its warmed up and i've put the windows down. I'm actually a little embarrassed by it, lol. Could always go back to recirc so no problem.

[Tommy]

Originally Posted by pzr2874 @Tommy; did you replace the front o2?

Upstream/wideband. The one right after the turblow.

[KCi]

Originally Posted by x09MS3GT Sorry to bump this old thread. But the past 2 months ive been banging my fucking head off a wall trying every possible idea as to what the hell is going on with my car, and this thread is exactly the problem im seeing as well 2 Months ago, i started my car up as normal in the cold. Was about 28 degrees out. Car started up without hesitation just as it always does. As the coolant warms up the AFR rises up to about 14.5 to 14.7 at idle, when all of a sudden, it starts dropping down, 13's, 12's, 10's , 9 's , 8's. STFT is fucking pegged at -25. Car is struggling to stay running while drowning itself in fuel. I turn it off. Restart the car, problem is gone. On the way home. Crusing in 4th gear, 40 mph, steady pedal input, watching A/F , its sitting at 14.6 , 14.7 . Then all of a sudden, it drops down to 14.0, climbs back to 15.0, then back down, then back up then back down, then back up. Then settles at 14.7. I get home, furious as all hell. Reflash current map. Problem is now non existant. 100 miles later, fuel trims are pretty tight. All with in +/- 4 across the board. Driving hte car to work. It starts doing the same fucking shit again. climbing up and down while crusing with steady pedal input, no movement. Sometimes after a shift, the AFR dips down to 13.8, and sits there as i cruise in a gear with steady pedal input, and it SLOWLY rises back up to 14.6 / 14.7. Yesterday morning, start the car, AFR pegged at 8.0:1 , drowning itself in fuel, struggling to stay running. Ive pulled the Primary 02 , cleaned it, ive checked at least 3 times now for boost leaks, ive cleaned my MAF twice. I even put a brand fucking new Filter replacement for the COBB SRI on. Im running out of ideas here. Has anyone got any ideas ? 02 sensor dying out ? MAF Sensor Eff'd ? And if so, how with so little miles. I dont get it.

Hey x09MS3GT, may I know if you had solved your issue? Recently I having exactly same issues as yours. Idle AFR super rich ~9 and loosing engine power and hardly move at low RPMs albeit floor it. It came back OK after resetting the ECU by plug off the battery. I tried with stock map, custom tuned map and etc, all bad.

Appreciate your comment here. I am really lost in the jungle and going back to dealer is not helping.

[KCi]

Bump. Can anyone share some thoughts here? I'm running out of ideas. No CEL or whatever. It just running super rich AFR ~9 and car bogging down at low RPMs. It came back OK after hard resetting it by pulling off battery.

Please help.

[mrQQ]

Well, seems lately more and more people are getting the "rich" issue.. I am still to find a solution..

[KCi]

UPDATE: This is maybe useful to the MSF community here. I sent my MS3 back to dealer and they have been very supportive in debugging the erratic idling and rich AFR. They changed MAF, O2 and other (which I forgot to ask) sensors and yet still the same. They even ran test on HPFP and coil packs and not helping.

At last, they found the culprit at throttle body. The throttle body apparently sending inaccurate signal back to ECU for AFR compensation. They noted that I had the coolant bypass done and they said this is bad to throttle body. The coolant apparently used for reducing heat produced by the drive-by-wire circuitry at throttle body.

No matther what, it does solved the problem. What do you think of coolant bypass at throttle body?

[hnda etr]

Originally Posted by KCi UPDATE: This is maybe useful to the MSF community here. I sent my MS3 back to dealer and they have been very supportive in debugging the erratic idling and rich AFR. They changed MAF, O2 and other (which I forgot to ask) sensors and yet still the same. They even ran test on HPFP and coil packs and not helping. At last, they found the culprit at throttle body. The throttle body apparently sending inaccurate signal back to ECU for AFR compensation. They noted that I had the coolant bypass done and they said this is bad to throttle body. The coolant apparently used for reducing heat produced by the drive-by-wire circuitry at throttle body. No matther what, it does solved the problem. What do you think of coolant bypass at throttle body?

I ran the coolant bypass for at least 30k miles with no problems... the coolant at operating temp is probably around 190 degrees.... I doubt it's doing anything to cool off the circuitry. In fact, to "cool off" the circuitry, it would have to be running at hotter than the ~190 degrees that the coolant is at.

Sounds like stealership bullshit to me...

[vtekken]

Originally Posted by KCi UPDATE: This is maybe useful to the MSF community here. I sent my MS3 back to dealer and they have been very supportive in debugging the erratic idling and rich AFR. They changed MAF, O2 and other (which I forgot to ask) sensors and yet still the same. They even ran test on HPFP and coil packs and not helping. At last, they found the culprit at throttle body. The throttle body apparently sending inaccurate signal back to ECU for AFR compensation. They noted that I had the coolant bypass done and they said this is bad to throttle body. The coolant apparently used for reducing heat produced by the drive-by-wire circuitry at throttle body. No matther what, it does solved the problem. What do you think of coolant bypass at throttle body?

Did you also have an aftermarket throttle body insulating gasket? I'm not positive, but is anything measured at the throttle body other than position and intake air temp? Sounds like BS to me.

[hnda etr]

Originally Posted by vtekken Did you also have an aftermarket throttle body insulating gasket? I'm not positive, but is anything measured at the throttle body other than position and intake air temp? Sounds like BS to me.

iirc, intake air temp is measured by the MAP sensor. The coolant is used to speed up warming of the air when the motor is cold, improving atomization and lowering smog gasses.

The only time not to do the bypass is if you live where you have freezing temps. The coolant will keep the TB from freezing up.

WHY Heat The Throttle Body!?

[mrQQ]

well, I haven't touched TB and it still happens to me, so I call BS..?

[btstarcher]

Originally Posted by hnda etr iirc, intake air temp is measured by the MAP sensor. The coolant is used to speed up warming of the air when the motor is cold, improving atomization and lowering smog gasses. The only time not to do the bypass is if you live where you have freezing temps. The coolant will keep the TB from freezing up. WHY Heat The Throttle Body!?

This is incorrect. The intake air temp is measured by the MAF sensor. The MAP sensor measures the boosted air temp.

[hnda etr]

Originally Posted by btstarcher This is incorrect. The intake air temp is measured by the MAF sensor. The MAP sensor measures the boosted air temp.

right right thanks... I knew that at one point lol

[timjs]

Lol...
200F+ coolant to "cool" the throttle body?

It's to prevent icing of the throttle body in cold climates.
Shit like that makes all dealers look bad.

[KCi]

Yeah, at some point, the cooling part does sound BS to me as well. The TB ain't cheap. Glad the dealer swap it for me and it works fine now. No more black smoke coming out from exhaust, stable idling and better fuel economy.

#vtekken , yeap, I have JBR thermal gasket on TB.

[DeathWish]

Ok so I'm sorry to revive such an old thread but I'm somewhat lost and I was wondering if anyone can help me. I saw really rich afr's and I replaced the fuel pump internals fixing the issue with pressure dropping but now the afr's are still low but after a WOT pull it shows in the datalog that it's only after letting off the accelerator. So during the pull it's perfectly ok, over 1600 psi and around 11 afr, I let off and one little cell of the datalog spreadsheet shows a 9 something afr. Then today I got my fmic and a new ots tune and when I turn sharply and accelerate with any sort of force, any boost, the car bogs, won't accelerate and the afr shows 8 something. I assume this is the tune and swas not getting along but if anyone has a more knowledgeable opinion it would be greatly appreciated. Again sorry for reviving a 3 year old thread.